Despite demographic studies showing that the aged suffer a disproportionate share of the handicaps of impaired vision, relatively little is known about changes in visual perception with advancing age. This project undertakes a developmental approach to spatio-temporal visual information processing, emphasizing the last half of the life-span developmental sequence. Spatial contrast sensitivity functions will be obtained at various ages up to the decade eight of life. Modern psychophysical procedures will distinguish between those functional losses in vision which are attitudinal in origin (caution of the aged) and those which are sensory. Differential loss in sustained and transient visual mechanisms will also be investigated. Finally, the effects of stimulus uncertainty and distraction on observers of various ages will be examined.